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Abstract

BACKGROUND:
Human Papillomavirus (HPV) is the most common sexually-transmitted agent. Infections with oncogenic HPV types 16 & 18 are causally linked to the development of cervical cancer, as well as a proportion of anal, oropharyngeal, vulvar, vaginal and penile cancers and their associated precancerous lesions. Immune suppression increases the likelihood of HPV-related diseases, and people with human immunodeficiency viral (HIV) infection or with HIV-positive partners are at a higher risk of precancerous lesions and cancers, as well as genital warts.
OBJECTIVES:
Determine the prevalence and distribution of high risk (HR) oncogenic HPV genotypes in HIV-positive adults in Atlantic Canada. Examine association between HR HPV genotypes and premalignant lesions and incident malignancy; Examine association between premalignant lesions and malignancy and patients’ demographics and underlying risk factors.
METHODS:
This prospective cohort study was designed for four years in Atlantic Canada HIV care clinics.
Total 300 were enrolled in the study and of them, 263 were included in the final analysis. Participants were required to complete a confidential questionnaire to obtain demographic and risk factor data. Annual collection of oropharyngeal and anal swab specimens from all participants and an additional cervical specimen from females were obtained. All specimens were tested for cytologic abnormalities, HPV DNA and HPV genotyping. The ASIR of the incident cancers was calculated using the Canadian general population as reference.
RESULTS: Of 263 patients 93.2% were males. The mean (SD) age of the study population at the enrollment time was 46.9 (9.4) years and 51.3 (9.1) years at the study’s end. A total of 227 (86.3%) participants were positive for HPV infection. Of these, 88.1% had HPV infection at one body site and 11.9% had HPV genotypes detected at two body sites simultaneously. Up to 50 HPV genotypes were detected, of which 32 (63%) were HR oncogenic types. Eight (16%) HPV types were significantly associated with the confirmed 31 (11.8%) cases of precancerous lesions and 8 (3.3%) incident cases of malignancy. The precancerous lesions significantly associated with patients CD4 cell count < 200 cells/mL (p=0.034), smoking (p=0.007), history of anogenital warts (p=0.002) and genital herpes (p=0.007).
CONCLUSIONS:
The overall incidence of cancer was 3.3%, all of them diagnosed in males. The ASIR (95%CI) of anal cancer is 535/100,000 (30-970) and ASIR (95%CI) of oral cancer is 533/100,000 (30-970).
KEY WORDS:
Human papillomavirus infection, anal cancer, cervical cancer, head and neck cancer, squamous cell carcinoma, HPV genotyping, HPV prevalence and incidence, HPV and malignancy, HPV risk factors, HIV-HPV co-infection, prevalence of cancer in MSM.